Process of preparing a concentrated water-based liquid detergent

ABSTRACT

PCT No. PCT/EP92/02309 Sec. 371 Date Apr. 15, 1994 Sec. 102(e) Date Apr. 15, 1994 PCT Filed Oct. 7, 1992 PCT Pub. No. WO93/08249 PCT Pub. Date Apr. 29, 1993.A process for preparing a storage-stable and free-flowing concentrated water-based liquid detergent containing 15 to 35% by weight of anionic surfactant, 20 to 35% by weight of nonionic surfactant, and from 5 to 20% by weight of alcohol. A dilute sodium hydroxide solution is heated to 70 DEG  to 85 DEG  C. to which is added a fatty acid and the alcohol. The mixture is stirred at 350 to 500 r.p.m. for 3 to 10 minutes. The anionic surfactant and nonionic surfactant are added to the mixture and stirred at 150 to 350 r.p.m.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

This invention relates to a homogeneous, concentrated water-based liquiddetergent, to a process for its production and to its use for the manualand machine washing of fabrics.

Water-based liquid detergents which contain a mixture of anionic andtypical nonionic surfactants and in which the nonionic surfactantcontent, based on the liquid detergent as a whole, is 20% by weight ormore, generally lack homogeneity to the extent that the liquid detergentundergoes phase separation, for example separation into two clear liquidphases or the flocculation of a solid. This phase separation eitheroccurs directly during production, during storage for several weeks(inadequate stability in storage) or on dilution with water. Anotherdisadvantage is that liquid detergents of this type often show such highviscosities that they can no longer flow without the application ofexternal shear forces.

It has now been found that it is possible to produce concentratedwater-based liquid detergents containing at least 20% by weight ofnonionic surfactants which do not have any of the disadvantagesmentioned above.

DESCRIPTION OF THE INVENTION

In a first embodiment, therefore, the present invention relates to aconcentrated water-based liquid detergent containing 30 to 60% by weightof anionic and nonionic surfactants, with the proviso that the nonionicsurfactant content of the detergent is 20 to 35% by weight, based on thedetergent as a whole, and the detergent contains monohydric and/orpolyhydric alcohols containing 1 to 6 carbon atoms in quantities of 5 to20% by weight, based on the detergent as a whole, as organic solventsand flows under the sole effect of gravity without any need for othershear forces to be applied.

The concentrated water-based liquid detergents preferably contain atleast 35% by weight and more preferably between 40 and 60% by weightand, with particular advantage, between 45 and 58% by weight ofsurfactants. The detergents are homogeneous, stable in storage(stability test over at least 3 months both at room temperature and atextremely low temperatures of 5° C. and 40° C.) and do not undergo phaseseparation, even on dilution with water. They may be used manually andin machines either in concentrated form or, if required by the consumer,in dilute form. Thus, the consumer may either use the concentrateddetergent directly in a quantity smaller than the quantity required inthe case of commercial non-concentrated liquid detergents or,alternatively, may transfer the concentrated detergent to a bottle oflarger volume, for example with twice the volume, fill up the bottlewith water to the required dilution of the detergent and use the nowdilute detergent, which is also stable in storage, in the quantities inwhich conventional, non-concentrated water-based liquid detergents arenormally used. The liquid concentrates are preferably mixed with waterin a ratio of 1:2 to 1:1. In machine washing, the concentrated liquiddetergent is dispensed either via the dispensing compartment of thewashing machine or via a commercial, external dispenser, for example inthe form of a dispensing ball.

The nonionic surfactant content of the detergent is preferably 22 to 32%by weight and more preferably 25 to 30% by weight. The nonionicsurfactants used are preferably adducts of on average 1 to 10 moles ofethylene oxide with primary C₁₂₋₁₈ fatty alcohols and mixtures thereof,such as coconut oil fatty alcohol, tallow fatty alcohol or oleylalcohol, or with primary alcohols (oxoalcohols) methyl-branched in the2-position. Particularly suitable adducts are C₁₂₋₁₄ alcohols . 3 EO or4 EO, C₁₃₋₁₅ alcohols . 3, 5 or 7 EO, C₁₂₋₁₈ alcohols . 3, 5 or 7 EO andmixtures thereof, such as mixtures of C₁₂₋₁₄ alcohol . 3 EO and C₁₂₋₁₈alcohol . 5 EO. The concentrated liquid detergents preferably contain 21to 30% by weight and, more particularly, 22 to 28% by weight ofethoxylated nonionic surfactants. The detergents preferably contain asfurther nonionic surfactants alkyl glucosides corresponding to thegeneral formula RO(G)_(x), where R is a primary linear or2-methyl-branched aliphatic radical containing 8 to 22 and preferably 12to 18 carbon atoms and G stands for a glucose unit. The degree ofoligomerization x, which indicates the distribution of monoglucosidesand oligoglucosides, is a number of 1 to 10 and preferably a number of1.2 to 1.4. The concentrated water-based liquid detergents maypreferably contain 1 to 5% by weight of alkyl glucoside.

Suitable anionic surfactants are the known sulfates, sulfonates andsoaps. The anionic surfactant content of the detergents is preferably 15to 35% by weight and more preferably 18 to 31% by weight. Preferredanionic surfactants are fatty alkyl sulfates, alkanesulfonates,saturated and/or unsaturated soaps and, in particular, mixtures thereof,such as mixtures of fatty alkyl sulfate and soap, mixtures ofalkanesulfonate and soap and mixtures fatty alkyl sulfate,alkanesulfonate and soap.

Suitable fatty alkyl sulfates are the sulfuric acid monoesters of C₁₂₋₁₈fatty alcohols, such as lauryl, myristyl or cetyl alcohol, and the fattyalcohol mixtures obtained from coconut oil, palm oil and palm kernel oiland also tallow which may additionally contain unsaturated alcohols, forexample oleyl alcohol. Mixtures in which 50 to 70% by weight of thealkyl radicals contain 12 carbon atoms, 18 to 30% by weight 14 carbonatoms, 5 to 15% by weight 16 carbon atoms, less than 3% by weight 10carbon atoms and less than 10% by weight 18 carbon atoms are preferablyused. The fatty alkyl sulfate content of the detergents is preferably 2to 10% by weight and more preferably 2 to 5% by weight.

The readily biodegradable alkanesulfonates are obtained from C₁₂₋₁₈alkanes, for example by sulfochlorination or sulfoxidation andsubsequent hydrolysis or neutralization. The sulfonate group isstatistically distributed over the carbon chain as a whole, thesecondary alkanesulfonates predominating. The concentrated water-basedliquid detergents preferably contain 8 to 20% by weight and morepreferably 10 to 16% by weight of alkanesulfonate.

Other suitable anionic surfactants are in particular soaps, preferablyin quantities of 8 to 20% by weight and more preferably in quantities of10 to 18% by weight. Suitable saturated fatty acid soaps are, forexample, the salts of lauric acid, myristic acid, palmitic acid orstearic acid and, in particular, soap mixtures derived from naturalfatty acids, for example coconut oil, palm kernel oil or tallow fattyacids. Soap mixtures of which 50 to 100% by weight consist of saturatedC₁₂₋₁₈ fatty acid soaps and 0 to 50% by weight of oleic acid soap areparticularly preferred.

The anionic surfactants may be present in the form of their sodium,potassium or ammonium salts and in form of soluble salts of organicbases, such as mono-, di- or triethanolamine. The anionic surfactantsare preferably present in the form of their sodium salts and/orpotassium salts, preferably their sodium salts.

The concentrated and homogeneous liquid detergents contain water andmonohydric and/or polyhydric alcohols preferably containing 2 to 4carbon atoms as solvents. Preferred alcohols are ethanol, propanol,1,2-propanediol, glycerol or mixtures thereof. The detergents preferablycontain 20 to 50% by weight, more preferably 25 to 45% by weight and,with particular advantage, 28 to 40% by weight of water. The monohydricand/or polyhydric alcohol content of the detergents is preferably 5 to17% by weight. In a particularly preferred embodiment, the detergentscontain 7 to 15% by weight of a mixture of ethanol and glycerol in anyratio.

The pH value of the concentrated detergents according to the inventionis generally in the range from 7 to 10.5, preferably in the range from 7to 9.5 and more preferably in the range from 7 to 8.5. Relatively highpH values, for example above 9, may be adjusted by the use of smallquantities of sodium hydroxide or alkaline salts, such as sodiumcarbonate or sodium silicate. The liquid detergents are clear and areflowable and can be poured under the sole effect of gravity without anyneed for other shear forces to be applied. Their viscosity is generallybelow 1,000 mPas (Brookfield viscosimeter, spindle 1, 20 revolutions perminute, 20° C.). The viscosity of the detergents is preferably in therange from 150 to 900 mPas and more preferably in the range from 150 to500 mPas.

The detergents are preferably free from water-soluble andwater-insoluble builders. In a particularly preferred embodiment, theydo not contain the (co)polymeric polycarboxylates known as co-builders,for example homopolymers or copolymers of acrylic acid or maleic acid.

In addition to the ingredients mentioned above, however, the detergentsmay contain known additives of the type typically used in detergents,for example salts of citric acid, salts of polyphosphonic acids, opticalbrighteners, enzymes, enzyme stabilizers, small quantities of neutralfilling salts and also dyes and fragrances, opacifiers and pearlescers.

Preferred salts of polyphosphonic acids optionally present are theneutrally reacting sodium salts of, for example,1-hydroxyethane-1,1-diphosphonate and diethylenetriamine pentamethylenephosphonate which are used in quantities of 0.1 to 1.5% by weight. Thetotal phosphorus content of the detergents is preferably less than 0.5%by weight.

Suitable enzymes are those from the class of proteases, lipases,amylases, cellulases and mixtures thereof. The enzyme content may befrom 0.2 to 2% by weight.

In addition to the monohydric and polyhydric alcohols, the detergentsmay contain other enzyme stabilizers. For example, sodium formate may beused in a quantity of 0.5 to 1% by weight. Proteases stabilized withsoluble calcium salts (calcium content preferably about 1.2% by weight,based on the enzyme) may also be used. However, it is of particularadvantage to use boron compounds, for example boric acid, boron oxide,borax and other alkali metal borates, such as salts of orthoboric acid(H₃ BO₃), metaboric acid (HBO₂) and pyroboric acid (tetraboric acid H₂B₄ O₇).

Where the detergents are used in washing machines, it can be ofadvantage to add typical foam inhibitors. Suitable non-surface-activefoam inhibitors are, for example, organopolysiloxanes and mixturesthereof with microfine, optionally silanized silica and also paraffins,waxes, microcrystalline waxes and mixtures thereof with silanizedsilica. Mixtures of various foam inhibitors, for example of silicones,paraffins or waxes, may also be used with advantage.

In one preferred embodiment, the detergents contain 2 to 8% by weight offatty alkyl sulfate, 12 to 18% by weight of soaps consisting of the saltof oleic acid, the salt of saturated C₁₂₋₁₆ fatty acids or mixturesthereof in a ratio by weight of oleate to saturated soap of 2:1 to 1:2,21 to 30% by weight of ethoxylated fatty alcohol, 1 to 5% by weight offatty alkyl glucoside, 8 to 12% by weight of ethanol and/or glycerol,0.5 to 1% by weight of protease and 0.2 to 1% by weight of citric acidsalt (based on the free acid).

In another preferred embodiment, the detergents contain 2 to 5% byweight of fatty alkyl sulfate, 8 to 16% by weight of alkanesulfonate, 10to 17% by weight of saturated soap or a soap mixture of saturated andunsaturated fatty acid soaps, 22 to 28% by weight of ethoxylated fattyalcohols, 1 to 5% by weight of fatty alkyl glucoside, 10 to 15% byweight of ethanol and/or glycerol and other additives, more particularlyenzymes, salts of citric acid, dyes and fragrances, pearlescers andoptionally up to 1% by weight of phosphonate.

In another embodiment, the present invention relates to a process forthe production of the concentrated water-based liquid detergent in whichsoap and the polyhydric alcohol optionally present, more particularlyglycerol, are added to a heated, dilute sodium hydroxide solution, whichhas preferably been heated to 70° to 85° C., and intensively mixed forabout 3 to 10 minutes at a high rotational speed of the stirrer, moreparticularly at 350 to 500 revolutions per minute (r.p.m.). The otheringredients are then added at a slower rotational speed of the stirrer,preferably at 150 to at most 300 r.p.m. The remaining surfactants exceptfor the alkanesulfonate optionally present are added at the same time inpreheated, liquid, molten or solvent form, preferably in a form heatedto between 65° and 90° C. and more particularly to between 75° and 85°C. Intensive stirring of the mixture is continued. Ethanol is preferablyadded at a temperature of 40° to 55° C. and more preferably at atemperature of 48° to 55° C. After further cooling to room temperature,the remaining ingredients, more particularly the temperature-sensitiveingredients, for example enzyme, dyes and fragrances, are added.

EXAMPLES

The liquid detergents D1 and D2 according to the invention had thefollowing composition (in % by weight):

    ______________________________________                                                              D1   D2                                                 ______________________________________                                        C.sub.12-14 Fatty alkyl sulfate, sodium                                                               5.0    2.0                                            salt                                                                          Alkane sulfonate, sodium salt (100%                                                                   --     12.0                                           active substance; used as Hostapur                                            SAS 93, a product of Hoechst, Fed.                                            Republic of Germany)                                                          Lauric acid             8.0    7.0                                            Oleic acid              6.0    7.0                                            C.sub.12-18 Fatty alcohol with on average                                                             27.0   25.0                                           7 EO                                                                          C.sub.12-14 Alkyl glycoside with x = 1.4                                                              3.0    3.0                                            Sodium hydroxide        2.2    2.2                                            Ethanol                 5.0    7.0                                            Glycerol                5.0    5.0                                            Citric acid             0.5    0.5                                            Protease                0.8    0.8                                            Amylase                  0.08   0.08                                          Water, dyes and fragrances,                                                                           Balance to 100%                                       pearlescers             by weight                                             pH                      7.9    8.1                                            ______________________________________                                    

The detergents were produced by initially heating a mixture ofdemineralized water and sodium hydroxide to 80° C. This was followed byaddition and neutralization of the fatty acids and by addition of theglycerol. The mixture was stirred for 5 minutes at 400 r.p.m. and thenat 200 r.p.m. The other ingredients, more particularly the citric acidand the pearlescer, were then added. Before any other components wereadded, the mixture was stirred until a homogeneous mixture was obtained.The fatty alkyl sulfate, the alkyl glucoside and the ethoxylated fattyalcohol were then successively added in a form heated to 80° C. Bycontrast, the alkanesulfonate was added in a non-preheated form. Aftercooling to 50° C., ethanol was added. After further cooling to roomtemperature, the enzymes and also the dyes and fragrances were added.

The homogeneous detergents D1 and D2 according to the invention werestable in storage for 3 months both at room temperature and at 5° C. and40° C. (stability test terminated after 3 months). The viscosity(Brookfield viscosimeter, 20° C., spindle 1, 20 r.p.m.) was 330 mPas forD1 and 160 mPas for D2. The detergents could be diluted with water inany ratio without any phase separation occurring over a period of 4weeks (stability test terminated after 4 weeks).

Comparison tests with D1, in which the surfactants were added in cold,non-preheated form and/or the ethanol was added at room temperature,produced either inhomogeneous products or could no longer be made up asliquid detergents because the viscosity of the mixture increased to suchan extent that it could not flow without the application of shear forces(paste formation).

We claim:
 1. The process of preparing a concentrated water-based liquiddetergent consisting essentially of from 15 to 35% by weight of anionicsurfactant, from 20 to 35% by weight of ethoxylated fatty alcohol,optionally from 1 to 5% by weight of alkyl glucoside, and from 5 to 20%by weight of a monohydric and polyhydric alcohol having 1 to 6 carbonatoms, comprising heating a dilute sodium hydroxide solution to 70° to85° C. and adding a soap-forming amount of fatty acid and saidpolyhydric alcohol to said solution, mixing the resultant mixture atfrom 350 to 500 r.p.m. for about 3 to 10 minutes, heating said anionicsurfactant other than alkanesulfonates, said ethoxylated fatty alcoholand said alkyl glucoside, if present, to 65° to 90° C. and adding themto the resultant mixture, mixing the resultant mixture at from 150 to300 r.p.m., and then adding said monohydric alcohol to said mixture at atemperature ranging from 40° to 55° C.
 2. A process as in claim 1wherein said ethoxylated fatty alcohol comprises an adduct of 1 to 10moles of ethylene oxide with primary C₁₂ --C₁₈ fatty alcohols.
 3. Aprocess as in claim 1 wherein said anionic surfactant is selected fromthe group consisting of fatty alkyl sulfates, alkane sulfonates, andsoaps.
 4. A process as in claim 1 wherein said monohydric alcohol isselected from the group consisting of ethanol, propanel, and minutesthereof, and said polyhydric alcohol is selected from the groupconsisting of 1,2-propane diol, glycerol, and mixtures thereof.
 5. Aprocess as in claim 1 wherein said liquid detergent contains 20 to 50%by weight of water, based on the weight of said liquid detergent.
 6. Aprocess as in claim 1 wherein said liquid detergent has a pH from 7 to10.5.
 7. A process as in claim 1 wherein said liquid detergent has aviscosity of below 1,000 mPas measured at 20° C. with a Brookfieldviscosimeter, spindle no. 1, at 20 r.p.m.
 8. A process as in claim 1wherein said monohydric alcohol is ethanol.
 9. A process as in claim 1including cooling said mixture to room temperature, and adding theretoan enzyme, dye and fragrance.